1. Field of the Invention
The present invention relates to a sealing and safety device for filling a hollow body with a liquid.
2. Discussion of the Background
A number of safety systems for fuel tanks have been described, addressing, generally speaking, the solution of problems linked to degassing of the tank during filling thereof and its venting to the air during a normal period of rest and of functioning of the engine that is consuming said fuel. In addition to these problems, there is an increasingly imperious need, regarding respect for the environment, to recover the vapours that are released during the above-mentioned operations, while minimizing leakages to the atmosphere.
Various systems that achieve reasonably complete sealing between a delivery nozzle and a filling orifice of a tank are known. U.S. Pat. No. 3,334,779, for example, discloses a diaphragm made from flexible material that is slit into three segments. Pushing the nozzle in opens the diaphragm and separates the segments on the inner wall of the filler neck, where they act as a seal for the delivery nozzle.
The known systems, however, present a number of disadvantages:                creation of an overpressure in the tank, giving rise to returns of liquid in the filler neck;        absence of recovery of liquid vapours via the nozzle;        no protection in the event of surges in the tank.        